Application of near-infrared spectroscopy in quality control and determination of adulteration of african essential oils

An evaluation has been made of the potential of near-infrared (NIR) technologies in the assessment of essential oil components and in the identification of individual essential oils. The results showed that cross-validation models are able to predict accurately almost all of the components of essential oils. In different cinnamon (Cinnamomum zeylanicum) and clove (Syzygium aromaticum) essential oils, which showed a similar composition, 23 components (representing 97.8-99.9% of the oil) were accurately predicted, as well as 20 components (93.0-99.1%) in Cinnamomum camphora (ravintsara), 32 components (92.3-98.1%) in Ravensara aromatica (ravensara), and 26 components (96.6-98.4%) in Lippia multiflora. For almost all of the components, the modelled and reference values obtained by GC-FID were highly correlated (r2 ≥ 0.985) and exhibited a low variance (less than 5%). The model was also able to discriminate between the ravintsara and ravensara essential oils. It was shown that two commercial oils labelled as R. aromatica were actually ravintsara (C. camphora), revealing the misidentification of these essential oils in the marketplace. The study demonstrates the application of NIR technology as a quality control tool for the rapid identification of individual essential oils, for product authentication, and for the detection of adulteration. Copyright © 2006 John Wiley & Sons, Ltd.link_to_subscribed_fulltex

Intraspecific variation in quality control parameters, polyphenol profile, and antioxidant activity in wild populations of Lippia multiflora from Ghana

This study evaluates the variation of quality, polyphenol profile and antioxidant activity in wild varieties of Lippia multiflora from different regions of Ghana and reviews the pharmacological properties of this species. Our results showed that while the essential oil composition is highly variable, the polyphenols profile remain similar among the discrete populations with verbascoside being the main component followed by nuomiside. Our study also demonstrated that the antioxidant activity of one gram of Lippia multiflora leaves is equivalent to 2.7-12.4 g of Trolox (a Vitamin E analogue). Since the amount of total phenols, antioxidant activities and phenylpropanoid glycosides in some Lippia populations were found to be comparatively low, and these are the compounds largely responsible for many of the plants medicinal attributes, those populations with higher contents of bioactive constituents and those processing techniques that can maximize their content should be used in the commercialization of this species to improve its nutraceutical properties. Our study also showed the importance of the evaluation of bioactive components from wild varieties of Lippia multiflora, and that such natural variation can be used as a source of new components and bioactivities to develop new or improved products by selection and/or breeding to improve the genetic materials that are commercialized. Because Lippia multiflora is not well know in the international markets, this plant species may serve as a unique 'African bush tea' in the western marketplace, and as a possible source of aroma chemicals. © 2006 American Chemical Society.link_to_subscribed_fulltex